Method and apparatus for winding resistors



Feb. 18, 1969 L. LA BARRE METHOD AND APPARATUS FOR WINDING RESISTORS Filed March 22,- 1967 a m R a 2 NN ow 2 INVENTOR.

LAWRENCE LABARRE BY 4Z4 ATTORNEY United States Patent 8 Claims ABSTRACT OF THE DISCLOSURE A resistor winding machine for automatically winding a resistor inside of a cylindrically-formed sticky tape. A method and apparatus for winding a wire around the inside of a circularly-formed tape and subsequently compressing the tape and wire to form a substantially flat resistor with a helically-Wound wire making up the resistive element.

This invention relates to a resistor winding machine and a method for winding a resistor.

In the past, resistors have been formed by winding a wire around a bobbin or mandrel. After the wire is thus wound, either by hand or mechanically, a sticky tape is wrapped around the exterior of the wire. Next, the bobbin or mandrel is removed and the remaining resistor coil is flattened to form a fiat, wire-wound resistor.

In the method and apparatus of this invention, no bobbin or mandrel is required. Thus, a tricky step in the process is completely eliminated, since the wire is wound directly on the interior surface of a sticky tape without the necessity of the intermediate bobbin removal step. Bobbin machines and methods have two serious disadvantages. First, the very thin wire used for resistor winding normally has already been stretched, at least to some extent, during manufacture when it was wound on the spool in which it is sold to the resistor manufacturer- Because of this pre-stretching, the wire has a severe tendency to break if further tension is applied. A minimum amount of tension must necessarily be applied to the wire during any bobbin or mandrel Winding operation. Accordingly, problems have been encountered with the wire breaking while being wound onto the bobbin or mandrel. Even more important, if the wire doesnt break during winding, the additional stretching changes the characteristics of the wire in the resistor. Such changes severely impair the ability to control the resistance per unit of the length resulting resistor. As a result, the resistor quality is impaired over a period of time and the resistor often breaks down in subsequent use.

Thus, for both these reasons, it is highly desirable to apply as little tension as possible to the wire while winding the resistor. The less the tension, the longer the life and the higher the reliability of the resulting resistor.

The resistor winding machine and method of the subject invention winds a resistor without a bobbin or mandrel, and without applying any substantial amount of tension to the wire during the winding process. Briefly, the resistor winding machine of the subject invention comprises a means for spinning a wire in a circular path, including an orifice through which the wire can pass freely; and a means for moving a substrate material, such as a tape, having sticky interior surface, longitudinally relative to the position of the circular path of the wire, whereby centrifugal force at least partially causes the wire to form a continuous helical coil adherent to the sticky interior surface of the substrate or tape, thereby forming a resistor coil on the interior surface of the substrate material.

The method of the invention comprises the steps of spinning the wire in a circular path; and moving the subice strate material or tape having the sticky interior surface longitudinally relative to the position of the circular path of the wire, whereby centrifugal force at least partially causes the wire to form a continuous helical coil adherent to the sticky interior surface of the substrate material.

The invention will be better understood from a reference to the more detailed description which follows, making reference to the drawing in which:

FIG. 1 is a top plan view, somewhat schematically illustrated, of the resistor winding machine of the subject invention; and

FIG. 2 is a side elevation view of the resistor winding machine of FIG. 1.

Referring to FIGS. 1 and 2, the substrate, or tape, having one side coated with a sticky adhesive is wound on spool 10 with the sticky side on the inside of the spool. Adhesive Mylar tapes are suitable and readily available. The tape moves through tape guide 11 into circular tape guide 12. Circular tape guide 12 is shaped so that the tape is formed into a cylinder 13 with the sticky surface on the inside of the cylinder.

The wire 14 is contained on bobbin 15. It is fed through guide 16 into a tubular guide 17. The wire is moved by the operation of motor 18 through worm gears 19 and 20 and belts 21 and 22. Wire 17 is held adjacent to roller 23 by a tension device 24, including roller 25 and spring 26. Spring 26 holds roller 25 adjacent to wire 14 and roller 23 as the wire emerges from tubular guide 17. The wire is moved by the motion of roller 23. After passing through rollers 23 and 25, the wire enters a means for spinning the wire in a circular path, or second tubular guide 27 which has one end located along the central axis of the cylinder of tape 13. The other end 28 of tube 27 is located at the circumference of the cylinder of tape 13, and includes an orifice through which the wire can pass freely.

The essential aspect of this invention is the rotation of tubular guide 27. This is accomplished by motor 18 through pulleys 30 and 31 and belts 22 and 32. Pulley 31 is attached to tube 27 which is supported, in a manner so that it is free to rotate, by support means 33. The wire which enters at one end of tubular guide 27 emerges :from the other end 28. Finally, the apparatus includes two pairs of rollers 35 and 36 which compress the cylinder of tape with the wire wound inside into a flat resistor configuration 37.

The operation of the machine of this invention, and the method of the invention are as follows. The wire 14 is fed through spinning tubular guide 27 by the operation of motor 18 upon roller 23. At the same time, tubular guide 27 is spun in support 33 by the action of motor 18 upon pulley 31. Accordingly, the wire emerging from end 28 of tubular guide 27 is thrown, by the combined action of centrifugal force and the forward motion imparted to the wire by roller 23, against the interior edges of cylindrical tape 13. Since the interior of this tape is sticky, the Wire will adhere to the interior edges of the cylinder. The wire forms a helical coil as a result of the continuous forward motion of the cylindrical tape 13 relative to the position of end 28 of rotating tubular guide 27. Obviously, if desired, guide 27 could be moved and the tape held stationary. However, in the preferred embodiment illustrated in FIGS. 1 and 2, the continuous forward motion of the tape is used to achieve the desired helical pattern of wire on the interior surface of cylindrical tape 13.

After the forward motion of the tape takes it past end 28 of rotating tubular guide 27, it passes through rollers 35 and 36 where the cylinder is flattened or compressed into the final flat resistor configuration 37. Obviously, however, if a cylindrical resistor is desired, this step may be omitted.

From the above description, it will be apparent that the machine and method of this invention make possible the winding of continuous resistor strips without need for the intermediate step of winding of the wire onto a bobbin or mandrel and rewiring the bobbin or mandrel. Continuous resistor strips can be made virtually infinite in length. Manual labor is reduced to almost zero in the method of the invention.

The resistance per unit length of the resistor produced with the method and apparatus of this invention can be easily and accurately controlled by controlling the relative speed of the tape 13 and the tubular guide 27.

Although many modifications can be made in the preferred embodiment of the method and apparatus of this invention, as set forth in detail above, the invention is only to be limited as specifically set forth in the claims which follow.

What is claimed is:

1. A resistor winding machine, comprising:

a means for spinning a wire in a circular path, said means including an orifice through which said wire can pass freely;

a means :for moving a substrate material having a sticky interior surface longitudinally relates to the position of said circular path of said wire, whereby centrifugal force at least partially causes said wire to form a continuous helical coil adherent to said sticky interior surface of said substrate material.

2. The resistor winding machine of claim 1 further characterized by the addition of a means for feeding said wire through said orifice, said feeding means at least partially causing said wire to become engaged with said sticky surface of said substrate.

3. The resistor winding machine of claim 1 further characterized by said substrate material being a tape with a sticky surface, and including shaping means for shaping said tape into cylindrical form around said circular path with the sticky surface interior.

4. The resistor winding machine of claim 1 further 4 characterized by said spinning means being a spinning tubular guide, said wire entering into one end of said tubular guide at the center of said circular path and emerging from the other end at the circumference of said circular path.

5. The resistor winding machine of claim 3 further characterized by a compressing means for flattening said cylindrical tape and wire into a substantially fiat resistor.

6. A fnethod of winding a resistor comprising the steps of spinning a wire in a circular path;

moving a substrate material having a sticky interior surface longitudinally relative to the position of said circular path of said Wire, whereby centrifugal force at least partially causes said wire to form a continuous helical coil adherent to said sticky interior surface of sad substrate, thereby forming a resistor coil on the interior surface of said substrate material.

7. The method of claim 6 further characterized by the additional step of mechanically feding said wire through an orifice, said wire emerging in said circular path.

8. The method of claim 7 further characterized by the additional steps of compressing said resistor coil including said wire and said substrate, thereby forming a substantially flat resistor.

References Cited UNITED STATES PATENTS 1,681,956 8/1928 Shrincr 29-618 2,131,887 10/1938 'Friederich et al. 26459 2,947,963 8/ 1960 Oarlcy 29-618 X 2,996,085 8/ 1961 Matheny 140-2 3,217,756 11/1965 Doerer et al 140-923 X JOHN F. CAMPBELL, Primary Examiner.

0 J. L. OLINE, Assistant Examiner.

US. Cl. X.R. 140-93; 156439 

